Evolution of amoxicillin/clavulanate in the treatment of adults with acute bacterial rhinosinusitis and community-acquired pneumonia in response to antimicrobial-resistance patterns

A naturalistic comparison of amoxicillin/clavulanate extended release versus immediate release in the treatment of acute bacterial sinusitis in adults: A retrospective data analysis

BACKGROUND

Choosing the most effective treatment for acute bacterial sinusitis (ABS) is helpful to avoid treatment failure. To date, studies comparing antibiotic options for ABS have compared amoxicillin/clavulanate (AMX/CA) immediate release (IR) versus other antibiotics, but have not included AMX/CA extended release (XR).

OBJECTIVE

The purpose of this study was to determine whether the clinical advantages of AMX/CA XR found in a clinical trial setting translate to a naturalistic setting, relative to AMX/CA IR.

METHODS

Data for this retrospective analysis were obtained from a managed care benchmark database that included >25 million patients from >30 health plans covering 7 US census divisions. Data from all patients aged > or =18 years with an index diagnosis of ABS between July 1, 2001, and December 31, 2003, were included. Episodes of ABS were classified as treatment successes (no additional prescriptions for antibiotics, ABS-related emergency department [ED] visits, or ABS-related inpatient hospitalizations within 30 days after the index prescription) or failures (> or =1 subsequent antibiotic prescription, an ABS-related ED visit, or an ABS-related inpatient hospitalization within 30 days after the index prescription). Treatment failures were subclassified as early or late. Mean costs were assessed for medical claims linked with a primary diagnosis of ABS and antibiotic pharmacy claims within the follow-up time period (through February 28, 2004). Descriptive statistics for demographic characteristics, utilization patterns, and success rates were calculated for each cohort. A multivariate general linear regression model was developed to assess differences in costs between the 2 cohorts.

RESULTS

: Of the patients with an index antibiotic prescription filled within 3 days of ABS diagnosis (n = 241,511), a total of 3224 in the AMX/CA XR cohort (mean [SD] age, 41.8 [11.6] years; women, 57.7%) and 23,638 in the AMX/CA IR cohort (mean [SD] age, 41.9 [11.6] years; women, 62.7%) were included in the analysis. The rate of treatment success in patients treated with AMX/CA XR was 82.8% versus 81.0% in patients treated with AMX/CA IR (P < 0.015). Treatment success costs were significantly lower than treatment failure costs regardless of an early or late designation and ranged from 98 dollars to 110 dollars per episode (P < 0.001). After adjustment for background covariates, the mean cost of treating an episode of ABS was significantly lower for patients receiving AMX/CA XR versus those receiving AMX/CA IR (166.32 dollars vs 177.34 dollars [US 2004 dollars]; P < 0.001), representing a mean cost savings of 11.02 dollars per patient treated with AMX/CA XR over AMX/CA IR for ABS, regardless of treatment outcome.

CONCLUSIONS

The results from this data analysis suggest that AMX/CA XR had significantly higher treatment success in ABS relative to AMX/CA IR in this naturalistic setting. AMX/CA XR was associated with significantly decreased total ABS-related costs in these adults.

A sensitive assay of amoxicillin in mouse serum and broncho-alveolar lavage fluid by liquid-liquid extraction and reversed-phase HPLC

A sensitive and simple high-performance liquid chromatography (HPLC) method was developed and validated for the analysis of amoxicillin in mouse serum and broncho-alveolar lavage (BAL) fluid. One hundred microlitres of sample were needed for the assay. Sample processing was carried out with liquid-liquid extraction. Cefadroxil was used as an internal standard. The chromatographic separation was achieved on a C18 reversed-phase column with a mobile phase consisting of phosphate buffer, 1-octanesulphonic acid sodium salt and acetonitrile. The detection was conducted at 210 nm. The ranges of the standard curves were 0.2-20 and 0.05-5 microg/ml for serum and BAL samples, respectively. The recoveries of amoxicillin from serum and normal saline were 87 and 88%, respectively. The coefficients of variation were 1.78-6.13% for intra-day and 0.82-6.42% for inter-day analyses. The accuracy was within 100+/-6%. This method was successfully applied to analyze amoxicillin in mouse serum and BAL samples from a pharmacokinetic study.